Boston Red Sox starting pitcher Drew Pomeranz stands on the mound as Baltimore Orioles' Nolan Reimold rounds third on his two run, home run in the second inning of a baseball game at Fenway Park, Tuesday, Sept. 13, 2016, in Boston. (AP Photo/Charles Krupa)

FORT MYERS, Fla. (AP) — Red Sox pitcher Drew Pomeranz exited Sunday’s start after two innings because of tightness in his left triceps, the latest setback for Boston’s staff in spring training.

The Red Sox said Pomeranz, in competition for a spot in the rotation, was pulled against Minnesota as a precaution.

“I don’t think it’s anything serious,” the lefty said.

The AL East champions had been counting on Cy Young Award winner Rick Porcello, David Price and newcomer Chris Sale to be their big three in the rotation, with Pomeranz, knuckleballer Steven Wright and left-hander Eduardo Rodriguez vying for the remaining two spots.

But Price is out indefinitely, likely to start the season on the disabled list with a strained left elbow. Manager John Farrell said it was “too early to determine” if Pomeranz might not be ready when Boston opens at home on April 3 against Pittsburgh.

“I don’t think this is going to affect opening day,” Pomeranz said. “I was just one inning away from having a normal outing. I’ve had little tweak in my triceps before. It gets tight and I come in the next day and it’s fine.”

Pomeranz has had issues with his left arm since the Red Sox acquired him in a trade last July with San Diego. He received a stem cell injection during the offseason and was delayed earlier in spring training, making his first Grapefruit League start on March 14.

The 28-year-old Pomeranz was an All-Star with the Padres last year, then was dealt to Boston and went 3-5 with a 4.59 ERA for his new club.

Pomeranz gave up three runs on two hits and three walks to the Twins. He was expected to go three innings.

“My triceps got tight toward the end of the first inning,” he said. “Talked to the trainers in-between innings and went back out and it stayed tight the whole time. Nothing crazy.”

“I think just my workload has been a lot more than usual this week. In the second inning, it didn’t loosen up so we decided to call it quits. I could have thrown one more but it’s only my second start so might as well give it rest,” he said.

Pomeranz said this discomfort was in a different spot than the injection.

“Back of the arm, triceps. Probably as a result of getting back into the swing of things,” he said.

“Like I said, I could have gone out there and thrown another one. I’ll come in tomorrow and hopefully everything will be fine. I don’t think it’s too serious,” he said. “I never thought I was going to be perfect from the beginning and be ready to go. I started to feel better this week. I increased the workload and intensity so maybe it just tightened up on me a little bit. Before that I felt really good, best my arm had felt to this point. It’s just part of early season, preseason.”

Said Farrell: “We would always act on the side of caution in that situation where a pitcher has stiffness or tightness in his shoulder.”

“He said he could go out for one more inning, but we didn’t see any reason to do that. Hopefully he can get his work between starts and stay on schedule,” he said.

The Red Sox have several other pitching candidates beyond the main contenders, although not all of them are having solid springs.

Veteran right-hander Kyle Kendrick, in camp as a non-roster invitee, has been perhaps the most promising of the group. In 18 innings of five Grapefruit League appearances, including four starts, he has allowed three runs on 12 hits and three walks with 16 strikeouts.

Lefty Roenis Elias is less than halfway through a three-week shutdown with an intercostal strain. Left-handers Henry Owens and Brian Johnson struggled this spring and were among the first round of roster moves. Right-hander Hector Velazquez, signed out of the Mexican League, also has had trouble.

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